Because the fifth outfielder is just that important.

The two players are both right-handed hitters, but that is about the extent of their similarities. They both have their fair share of strengths and weaknesses, but the Yankees only have room for one on their roster.

Marcus Thames's biggest strength is his power. For his career, he has hit a home run once per every 15 at-bats and he has an ISO of .248 which is well above average. On the other hand, Jamie Hoffmann hit one home run for every 60 minor league at-bats with a career minor league ISO of .118.

What's more striking are Thames' splits versus lefties. It has been well documented that the Yankees could use a lefty-masher on their bench to compensate for the relative weaknesses of Curtis Granderson and Brett Gardner. While Gardner has not shown much of a platoon split over the course of his career, the Yankees must see something there because they have made the habit of hiding him versus left-handed pitching.

For his career, Thames has a .360 wOBA against lefties as opposed to a .323 wOBA versus righties. This is a stark difference that makes Thames a legit pinch hitting option against left handed pitching.

If the Yankees are looking for a player they can use to pinch hit, back up the corner outfield spots and first base, Thames is the guy they will choose.

Hoffmann, on the other hand, offers a different array of skills to the team. Baseball America just named him the best defensive outfielder in the Yankees system after consistently ranking him the best in the Dodgers system. This is a clear difference from Thames, who has been worth -15.8 runs in the corner outfield over his career and has a career outfield UZR/150 of -9.5.

Hoffmann is an unknown when it comes to hitting at the major league level, though. CHONE predicts an unacceptable .304 wOBA for him, which is not good enough to justify giving him a roster spot.

Whichever of these two players doesn't make the 25-man roster will be gone at the end of spring training.The main difference is that if the Yankees make Hoffmann their fifth outfielder and he remains with the team for the entire 2009 season, they would be able to retain him for the following five seasons.

If the Yanks decide to hold onto Thames, they will lose team control over him after the 2010 season. So what it really comes down to is what the Yankees see in Hoffmann. If they see a player who will be slightly less valuable to Thames in 2010, but one who can provide value for multiple seasons, they'll keep him.

If they have soured on Hoffmann a bit since the Rule 5 draft and think he doesn't provide enough offense to be a part of their bench, they'll try to work out a deal with the Dodgers to keep him, or send him back to Los Angeles while adding Thames to the 25-man roster.

The choice is up to the Yankees, but I think I'd lean towards keeping Hoffmann. Thames would not definitively opt out, seeing that he could see an opportunity with the Yankees after a single injury or ineffectiveness from Hoffmann.

Either way, the winner of this battle is just going to be the fifth outfielder. If one of them ends up playing a major role in 2010, that means injuries have befell the Yankees and would not be a good sign.

Baseball Prospectus, while unveiling a new team of writers also has unveiled a new statistic called SIERA that Greg touched on before here.

As a quick refresher, here is what SIERA does:

1. Allows for the fact that a high ground-ball rate is more useful to pitchers who walk more batters, due to the potential that double plays wipe away runners.

2. Allows for the fact that a low fly-ball rate (and therefore, a low HR rate) is less useful to pitchers who strike out a lot of batters (e.g. Johan Santana's FIP tends to be higher than his ERA because the former treats all HR the same, even though Santana’s skill set portends this bombs allowed will usually be solo shots).

3. Allows for the fact that adding strikeouts is more useful when you don't strike out many guys to begin with, since more runners get stranded.

4. Allows for the fact that adding ground balls is more useful when you already allow a lot of ground balls because there are frequently runners on first.

5. Corrects for the fact that QERA used GB/BIP instead of GB/PA (e.g. Joel Pineiro is all contact, so increasing his ground-ball rate means more ground balls than if Oliver Perez had done it, given he's not a high contact guy).

6. Corrects for the fact that FIP and xFIP use IP as a denominator which means that luck on balls in play changes one's FIP.

Needless to say this information is extremely useful in determining skills that pitchers can control and predicting future ERA. What we didn’t know a few weeks ago was that Baseball Prospectus also has SIERA numbers for minor leaguers, included in their annual season preview book. Let’s take a look at the SIERAs they provided.

Manny Banuelos,  2.67 ERA, 3.22 SIERA

Jeremy Bleich,  6.65 ERA,  4.18 SIERA

Wilken De La Rosa,  3.48 ERA,  4.11 SIERA

Zach McAllister,  2.23 ERA,  3.82 SIERA

Hector Noesi,  3.92 ERA,  2.64 SIERA

Ivan Nova,  AA- 2.36 ERA,  4.30 SIERA/ AAA- 5.10 ERA,  4.68 SIERA

Romulo Sanchez,  4.04 ERA, 4.00 SIERA

Andrew Brackman,  5.91 ERA,  4.40 SIERA

DJ Mitchell,  2.87 ERA,  3.54 SIERA

David Phelps,  2.80 ERA, 3.67 SIERA

SIERA’s are pretty complicated and involve a lot of factors so I don’t think I could illuminate every single thing causing the discrepancies that appear here. However some of it has to do with adjusting for park, league, defense, ground ball percentages as well as BABIP, K% and BB%.

A couple of things really stand out however. Hector Noesi is one of the few pitchers who has his SIERA almost a full run lower than his ERA. This isn’t a fluke either, as Noesi has consistently had sub 3.00 SIERA’s at each level for the past 2 seasons. Noesi is a fly ball pitcher and control specialist but has also struck out almost a batter per inning at each level from 08-09 as well. Andrew Brackman who had a horrific season shows a more reasonable SIERA of 4.40 compared to his 5.91 ERA in Charleston. Some of this is adjusting for defense I would assume as well as his elevated BABIP of .325 and a reasonable K%. However there’s really no glossing over such a bad season. If your still burning a torch for Brackman, BP does it’s best to douse it with water:

“The most wrong-headed first round pitching selection since Bill Bene, Tomy John surgery survivor Andrew Brackman was healthy enough to completely destroy any remaining illusions about his being a prospect at all- mechanical consistency is no more than a concept”

Ouch. Zach McAllister had a really low BABIP of .266 and playing in Trenton it’s not surprising the 2.23 ERA might be misleading. BP actually has McAllister with only a 47% GB rate in Trenton as well which is surprising from sinkerball specialist. McAllister has consistently had SIERA’s in the mid 3’s, which is obviously very good but not as nice as the 2.23, 1.84 and 2.45 ERA’s he’s posted the past two years.

In the next few weeks we’ll post some of the projections and discuss what the various systems have to say about the Yankee prospects they have numbers for. We’ll also be wrapping up our last 5 Yankee prospect profiles as well as starting to cover their spring training performances. It’s almost a month until real baseball and we’re getting pretty excited.

A couple of things here as spring training starts to grind into gear. Chad Jennings, the once incomparable reporter for the Scranton Wilkes/Barre Yankees has some notes on some farm hands:

· Alan Horne is apparently ready to start the year after again suffering through injuries last season. Seems like we hear this every year with Horne….no word yet on what level he’ll start at, but I’d guess Trenton if I were a gambling man.

· Jairo Heredia left Tampa to be with his sick mother in the Dominican Republic but is healthy and ready to start the season as well.

· Dellin Betances and George Kontos also are getting closer to returning, Betances to start throwing this week while Kontos should be ready to begin his rehab off a half mound in March.

Justin Inaz over at The Hardball Times put out a report evaluating minor league run environments. It’s an extremely illuminating piece. Every level in the Yankee system is in the bottom half of minor league of run environments. Here are the leagues with Yankee teams from least run friendly to most, with the overall rank in parthenes:

Florida State League (1)

Gulf Coast League (2)

International League (3)

New York Penn League (4)

Eastern League (6)

South Atlantic League (10)

These are just league wide trends for the past 3 years to be clear. We all know that individual park factors are just as important to consider however- for instance Trenton boasts one of the best pitching parks in all of baseball.

While we’re at it, here are the MILB park factors for the Yankee teams from 06-08 from BBTF:

1.02

0.93 

The results are about as we would expect. Trenton suppresses runs the most but I was relatively surprised about Charleston which also suppresses runs quite a bit and is actually the worst park for home runs.

The bottom line is that when evaluating performances across minor league levels, park factors as well as league run environment should be taken into consideration.

Jairo Heredia, RHP

6'1", 190 lbs

Jairo Heredia was signed in 2006 as part of the international free agent class and received a 285,000 dollar bonus. Originally from the Dominican Republic, Heredia was an attractive prospect due to his advanced command and polish for a 16 year old international signee. Shoulder problems have plagued Heredia since 2007 however and although his talent remains tantalizing, injuries are starting to take a toll in terms of development time.

Heredia landed squarely on the map with his 2007 debut season, posting impressive numbers after spending only part of 2006 in the Dominican summer league.

Season      K/9   BB/9  K/BB HR/9 AVG WHIP BABIP LOB% FIP

2007  (R)   10.10  2.14  4.73  0.78  .230  1.08  .308   80.2 %  2.98

2008  (A)   8.36   3.78  2.21  0.62  .255  1.39  .322   64.9 %  3.64

His 2007 season was a rousing success that was bracketed by shoulder issues that eventually shut him down in August. He also spent time nursing an injury in April of 2008 but showed no ill effects upon returning, almost matching the successful run he posted a year earlier. As an 18 year old in Charleston everyone was impressed with his success and it was mostly accredited to his plus secondary offerings as well as polished command. Early hubristic comparisons had Heredia as the next coming of Pedro Martinez and after 2008 he leapt onto many top 10 Yankee prospect lists.

Pegged to start 2009 with the Tampa Yankees, the 19 year old was set back with early shoulder issues. They weren’t serious enough to warrant surgery but they did prove detrimental to his development, causing him to miss months rehabbing the inflamed shoulder. He only ended up making 10 starts between the GCL, A and A+ levels. 2009 was kind of a lost year for Heredia because the development of his changeup stalled and the attempts to add more velocity to a well commanded 4 seam fastball took a back seat to injury rehab.

Scouting

Heredia throws a fastball with good movement in the low 90s, a true tumbling 12-6 curveball around 75-79 and a changeup that's a very good pitch but still a work in progress. Since 2006 his velocity has consistently sat at around 90-93 on his fastball but many remained optimistic he would add velocity as he filled out and got older. So far that has yet to happen. Heredia remains a projectable mid rotation starter because of his advanced command and polish. He has a very good feel for setting up hitters, locating both his fastball and curveball to both sides of the plate and getting hitters to chase out of the zone. The changeup is an addition to his arsenal that he originally shied away from using, but with some refinement in 2008, he was able to effectively develop it. Beginning 2009 Heredia’s main task before the injury was to progress further with his changeup. His makeup and attitude have also won praise throughout the organization and his outlook remains positive as he enters 2010 as a 20 yr old most likely in Tampa.

The Maple Street Press 2010 Yankees Annual is now available for order. Why am I telling you this? Because, for some crazy reason, those awesome Maple Street Press people had me contribute a story on Phil Hughes, detailing what went right for him in 2009 and what the Yankees should do with him long-term. It came out pretty good, if I may say so myself.

Now, if you're thinking that you read enough of my nonsense here at Pending Pinstripes, buy the 2010 Yankees Annual for the other content. Former Pending Pinstripes scribe and current TYU writer EJ Fagan contributed two great pieces to the annual: one profiling the prized Jesus Montero and the other detailing the state of the farm system.

Now, if you're worried that it is going to be some measly pamphlet that just has a few bloggers contributing, you're wrong. The editor, Cecilia Tan, did a wonderful job putting the entire thing together. The design, content, and layout matches up to any major publication out there. Given the writers' devotion to the Yankees, the content may even top them. I read the entire thing and thoroughly enjoyed it.

The writing is top-notch, the pictures are great, and I'm in it. What more could you want? At $12, I don't think you'll find a better Yankees book available right now. You can go ahead and order it online, or wait until it hits newsstands on March 3rd.

On a side note, I'm heading to Costa Rica for a week and probably won't be posting while I'm away. Don't let that stop you from coming back, as I'm leaving you in perfectly capable hands with Sean holding it down.